1. Field of the Invention
This invention relates generally to radar displays and, more particularly, to a radar display wherein it is desired to know the position that a directable radar antenna's beam strikes the surface being detected. The invention finds particular utility in search and rescue radar systems over waterways such as oceans.
2. Description of the Prior Art
Search and radar systems presently employed utilize an antenna which is directable by the pilot at tilt angles from the direction of the travel of the craft to intersect the surface being searched. In most cases, reflections from objects on the surface back to the receiver in the aircraft produce, on the radar display or "scope," a blip indicating where the beam is directed.
In search and rescue missions over terrain that has no significant ground return, such as in search missions over the ocean, the pilot has had to estimate or guess where, on his display, the radar beam is intersecting the water. This estimation may be off by a considerable margin, thus making it difficult for the pilot to properly direct his antenna for detecting lost objects.